Notwithstanding any other provision of law, whenever base acreages are in effect for corn, the Secretary shall require, as a condition of eligibility for price support on corn, that the producer (1) devote an acreage of cropland (tilled in normal rotation), at the option of the producer, to either the acreage reserve program for corn or the conservation reserve program, equal to 15 per centum of such producer’s farm base acreage for corn, and (2) not exceed such farm base acreage for corn: Provided, That price support may be made available to any producer who does not meet the foregoing requirements at such level, not in excess of the level of price support to producers who meet such requirements, as the Secretary determines will facilitate the effective operation of the price support program. Corn acreage allotments shall not be effective for the 1956 crop.